The image might be the way most of us remember that consummate showman, the entertainer’s entertainer, Sammy Davis Jr.

He’s laughing, often as not surrounded by white actors, singers, comics or politicians — some of them his peers — most of them less dazzling in at least one of the singer/dancer/actor and funnyman’s proficiencies.

Somebody — a fellow Rat Packer (Sinatra, Dino, Lawford or Bishop), Nixon, this comic or that Civil Rights icon — has said something funny, maybe only mildly amusing, maybe faintly/comically racist in the case of his Vegas/”Ocean’s 11″ Pack. And Sammy D’s laugh would consume his face, doubling him over, eyes closed, making you think you’d missed the best joke or quip this showbiz legend had ever heard.

But if you listen to audio of such occasions, as Yale professor and cultural historian Matthew Frye Jacobson did, you won’t “hear” that laugh. It was, often as not, a “silent laugh,” a bit of acting, a face Davis put on.

The man who integregated multiple professions, broke down cultural barriers in scores of ways, even by dating and marrying white women, but who grew up in the Jim Crow era that wasn’t merely limited to the South, was faking it to get by, to give white America the sense that he and people like him could laugh all the ugliness off, and that white America should catch on to the joke that racism has always been.

Jacobson’s academic “cultural history” of Davis through “The Long Civil Rights Era” (starting earlier than earlier historians suggested, and ending perhaps a bit later, if at all) puts the former child performer who performed his way to “living legend” in context. He parks Davis within his time as well as ahead of it, disparaged by the black community for going along to get along, clowning with famous liberal friends who made pushing the racial envelope — mostly at Sammy’s expense — part of their act, cuddling up to Nixon, preaching and believing with all his heart that his talent would render race irrelevent.

The book is a dense and heavily-notated history of Sammy’s life, parsing his biography and his spin on a life that saw him in blackface (perhaps posing as a dwarf, to get around child labor/welfare and education laws) as a tyke, nurtured and protected by the trio that his father, Sammy Sr., and Will Mastin sang, danced and joked across America, then a nightclub, recording artist, Broadway and even film star by the 1950s.

Jacobson quotes extensively from Davis’s many TV, print and radio interviews over the years, his “as told to” autobiography, “Yes, I Can,” and a revealing and authoritative profile that he sat for with “Playboy” journalist and future “Roots” author Alex Haley, who co-authored “The Autobiography of Malcolm X.”

Davis, who says he first faced real racism when he was in the Army during World War II, believed pretty much to the end of his days “that if I can get ‘big’ enough, my color” wouldn’t matter. As Jacobson points out, time and again, the evidence almost always proved otherwise.

The object here is to rescue Davis from the racial/cultural dismissal that attached itself to his self-absorbed (a showbiz failing) clowning, laughing-it-off persona, a dismissal that emerged in the 1950s and was chiseled in stone by the time he embraced the racist, corrupt, power-mad and “Southern Strategy” deploying Richard Nixon in 1972.

Davis wore variations of that “Uncle Tom” label for much of his life, which he resented. As he’d integrated Vegas, arm-twisted his way into busting down the seriously-segregationist hotel policies there and elsewhere and pushed a color-blindness in his romantic life that chipped away at the state-by-state “miscegenation” laws against interracial marriage, he felt he deserved better. He’d been a black Hollywood and recording industry pioneer, not just in representation but in the sorts of roles he played. Jacobson suggests Davis had a “resentful” point about his belittling critics.

His life wasn’t as unmessy as Poitier’s or Belafonte’s. Reviewing the new George Foreman biopic, “Big George Foreman” just after finishing this book, it strikes me that Davis was Foreman to his more lionized by his black peers Poitier and Belafonte’s Muhammad Ali. Foreman was branded as a race traitor, tone deaf, all of that, largely because he wasn’t Ali, because he’d waved an American flag after winning the boxing gold medal at the 1968 Olympics. He was and is dismissed as both “establishment” and a kind of a clown, the black boxer white America preferred, and later in life learned to love.

So it is with Davis — a palatable, lighthearted and non-threatening black face in an era when activists were giving American white supremacist politics, policies and cultural inequities their first serious challenge.

I used the words “academic” and “dense” in describing Jacobson’s book with reason. He dives into black activism, black cultural philosophy (James Baldwin is frequently quoted), theories behind what drives racism, the works.

But thorough as it is, it’s a dry read, with some passages taking the reader through pages when Davis himself isn’t mentioned as this or that racial law and practice is dissected and peers and those who preceded Davis (Bill “Bojangles” Robinson, most famously) are given biographical sketches and the history of tap dance or minstrel shows or the African American diaspora or Jim Crow are explored.

It helps to have read at least one of the other Davis biographies or his autobiography before plunging into “Dancing Down the Barricades.”

But Jacobson zeroes in on the essence of the man, the “I only cared about me” narcissism/egoism that drives most entertainers, and details a more integral role in the Civil Rights Movement than most give Davis credit for.

After all, his mere presence in America’s clubs, concert halls, casinos, cinemas and living rooms was something Martin Luther King. Jr. and others appreciated for what it was — groundbreaking, “barricade” breaching.

And the same year Davis gave Nixon that ill-advised hug, he gave Archie Bunker the disarming, humiliating and hilarious kiss that rocked America and underscored the early messaging of Norman Lear’s landmark comedy.

Racism, and racists, are laughable. Watch me laugh at them.

“Dancing Down the Barricades: Sammy Davis Jr. and the Long Civil Rights Era, A Cultural History.” By Matthew Frye Jacobson. University of California Press. 314 pages, with index. $20.95